Biomechanical responses of young adults with unilateral transfemoral amputation using two types of mechanical stance control prosthetic knee joints.

BACKGROUND: Prosthetic knee joint function is important in the rehabilitation of individuals with transfemoral amputation. OBJECTIVES: The objective of this study was to assess the gait patterns associated with two types of mechanical stance control prosthetic knee joints-weight-activated braking knee and automatic stance-phase lock knee. It was hypothesized that biomechanical differences exist between the two knee types, including a prolonged swing-phase duration and exaggerated pelvic movements for the weight-activated braking knee during gait. STUDY DESIGN: Prospective crossover study. METHODS: Spatiotemporal, kinematic, and kinetic parameters were obtained via instrumented gait analysis for 10 young adults with a unilateral transfemoral amputation. Discrete gait parameters were extracted based on their magnitudes and timing. RESULTS: A 1.01% ± 1.14% longer swing-phase was found for the weight-activated braking knee (p < 0.05). The prosthetic ankle push-off also occurred earlier in the gait cycle for the weight-activated braking knee. Anterior pelvic tilt was 3.3 ± 3.0 degrees greater for the weight-activated braking knee. This range of motion was also higher (p < 0.05) and associated with greater hip flexion angles. CONCLUSIONS: Stance control affects biomechanics primarily in the early and late stance associated with prosthetic limb loading and unloading. The prolonged swing-phase time for the weight-activated braking knee may be associated with the need for knee unloading to initiate knee flexion during gait. The differences in pelvic tilt may be related to knee stability and possibly the different knee joint stance control mechanisms. CLINICAL RELEVANCE: Understanding the influence of knee function on gait biomechanics is important in selecting and improving treatments and outcomes for individuals with lower-limb amputations. Weight-activated knee joints may result in undesired gait deviations associated with stability in early stance-phase, and swing-phase initiation in the late stance-phase of gait.

Long-term clinical evaluation of the automatic stance-phase lock-controlled prosthetic knee joint in young adults with unilateral above-knee amputation.

PURPOSE: The purpose of this study was to clinically evaluate the automatic stance-phase lock (ASPL) knee mechanism against participants' existing weight-activated braking (WAB) prosthetic knee joint. METHOD: This prospective crossover study involved 10 young adults with an above-knee amputation. Primary measurements consisted of tests of walking speeds and capacity. Heart rate was measured during the six-minute walk test and the Physiological Cost Index (PCI) which was calculated from heart rate estimated energy expenditure. Activity was measured with a pedometer. User function and quality of life were assessed using the Lower Limb Function Questionnaire (LLFQ) and Prosthetic Evaluation Questionnaire (PEQ). Long-term follow-up over 12 months were completed. RESULTS: Walking speeds were the same for WAB and APSL knees. Energy expenditure (PCI) was lower for the ASPL knees (p = 0.007). Step counts were the same for both knees, and questionnaires indicated ASPL knee preference attributed primarily to knee stability and improved walking, while limitations included terminal impact noise. Nine of 10 participants chose to keep using the ASPL knee as part of the long-term follow-up. CONCLUSIONS: Potential benefits of the ASPL knee were identified in this study by functional measures, questionnaires and user feedback, but not changes in activity or the PEQ.

[Methylenetetrahydrofolate reductase polymorphisms as risk factors for myelomeningocele]. / Estudio de asociación de base familiar entre polimorfismos de MTHFR y mielomeningocele en Chile.

BACKGROUND: Mandatory fortification with folic acid (FA) was implemented in Chile in 2000. Thereafter, the rate of spina bifida decreased by 52 to 55%. Genetic abnormalities in folate metabolism may be involved in the etiology of spina bifida. AIM: To evaluate the association between myelomeningocele (MM) and c.A1298C and c.C677T polymorphisms within the coding gene for 5,10-methylenetetrahydrofolate reductase (MTHFR) in the Chilean population. MATERIAL AND METHODS: These polymorphisms were genotyped in 105 patients showing isolated MM, born after the onset of FA fortification, and in their parents. The transmission disequilibrium test (TDT) was performed to evaluate alterations in the transmission of both alleles and haplotypes MTHFR polymorphism. We also evaluated the presence of parent-origin-effect (POE) of alleles using the Clayton's extension of the TDT. RESULTS: TDT analysis showed no significant distortions in the transmission of alleles or haplotypes. Moreover, although the POE showed increased risk for maternally derived allele, this risk was not statistically significant. CONCLUSIONS: The studied variants in the MTHFR gene (c.C677T and c.A1298C) do not constitute risk factors for MM in this sample of Chilean patients and their parents.

Estudio de asociación de base familiar entre polimorfismos de MTHFR y mielomeningocele en Chile / Methylenetetrahydrofolate reductase polymorphisms as risk factors for myelomeningocele

Background: Mandatory fortification with folic acid (FA) was implemented in Chile in 2000. Thereafter, the rate of spina bifida decreased by 52 to 55%. Genetic abnormalities in folate metabolism may be involved in the etiology of spina bifida. Aim: To evaluate the association between myelomeningocele (MM) and c.A1298C and c.C677T polymorphisms within the coding gene for 5,10-methylenetetrahydrofolate reductase (MTHFR) in the Chilean population. Material and Methods: These polymorphisms were genotyped in 105 patients showing isolated MM, born after the onset of FA fortification, and in their parents. The transmission disequilibrium test (TDT) was performed to evaluate alterations in the transmission of both alleles and haplotypes MTHFR polymorphism. We also evaluated the presence of parent-origin-effect (POE) of alleles using the Clayton’s extension of the TDT. Results: TDT analysis showed no significant distortions in the transmission of alleles or haplotypes. Moreover, although the POE showed increased risk for maternally derived allele, this risk was not statistically significant. Conclusions: The studied variants in the MTHFR gene (c.C677T and c.A1298C) do not constitute risk factors for MM in this sample of Chilean patients and their parents.

Family-based association study between SLC2A1, HK1, and LEPR polymorphisms with myelomeningocele in Chile.

Obese/diabetic mothers present a higher risk to develop offspring with myelomeningocele (MM), evidence supporting the role of energy homeostasis-related genes in neural tube defects. Using polymerase chain reaction-restriction fragment length polymorphism, we have genotyped SLC2A1, HK1, and LEPR single-nucleotide polymorphisms in 105 Chilean patients with MM and their parents in order to evaluate allele-phenotype associations by means of allele/haplotype transmission test (TDT) and parent-of-origin effects. We detected an undertransmission for the SLC2A1 haplotype T-A (rs710218-rs2229682; P = .040), which was not significant when only lower MM (90% of the cases) was analyzed. In addition, the leptin receptor rs1137100 G allele showed a significant increase in the risk of MM for maternal-derived alleles in the whole sample (2.43-fold; P = .038) and in lower MM (3.20-fold; P = .014). Our results support the role of genes involved in energy homeostasis in the risk of developing MM, thus sustaining the hypothesis of diverse pathways and genetic mechanisms acting in the expression of such birth defect.

A descriptive study of traumatic lower limb amputees from the Hospital Hel Trabajador: clinical evolution from the accident until rehabilitation discharge.

The purpose of the study was to describe the demographics, the causes of amputations, the amputation levels, the clinical outcomes, the durability of prostheses in unilateral lower limb amputee among workers entitled to non-state related work insurance, the ACHS, Chile, between 1974 and 2001. It was a retrospective descriptive study based on selected clinical files. One hundred files, with the minimal data required, were selected with a diagnosis of traumatic lower limb amputation, the levels ranging from Boyd's foot amputation to hip disarticulation, as defined by the Occupational Accidents Act from 1974 to December 2001. The mean age was 35.5 years, 96% were males, with an average follow-up of 7.7 years. In 50% of the cases the education level did not exceed elementary school. Ninety-eight percent were blue collar workers. The traumatic injury resulting in amputation took place during work in 89% of the cases the main causes being crushing injury (50%), traffic accident (19%), run over by car (14%) and burns (6%). The most common amputation levels were trans-femoral (40%) and trans-tibial (47%). Amputations were performed within the first 24 h in 49% of the cases. The hospitalization stay reached 8 weeks in 56.7%. Early complications were dehiscence (9.4%), superficial infection, (14.6%) and deep infection (26%). Late complications detected were soft tissue lesions (34.1%), exostosis (3.6%), painful neuroma (12.5%) and phantom limb pain (12.5%). Prostheses durability was on average 3 years. The average period to resume work was 1 year for 60% of the cases.

Colelitiasis en lesionado medular crónico / Cholelithiasis in chronic spinal marrow injured individuals

Estudios norteamericanos reportan mayor frecuencia de colelitiasis en Lesionados Medulares (LM) que en población sin lesión medular. Plantean esta condición como factor de riesgo en el desarrollo de litiasis biliar. Objetivo: determinar la frecuencia de colelitiasis en LM crónicos controlados en la asociación Chilena de Seguridad (ACHS) y comparar frecuencia de colelitiasis en población sin LM. Método: se incluyen en el estudio 76 LM completos American Spinel Injury Association (ASIA) A o B y 24 LM incompletos, de más de un año de evolución, todos varones, mayores de 20 años. El grupo control (GC) lo componen 100 varones voluntarios sin lesión medular, sin historia biliar. Se realizaron estudios ecotomográficos de vesícula y vía biliar. Resultados: La frecuencia de colelitiasis en LM completo es 25 por ciento (19 de 76 casos), 25 por ciento ( 6 de 24) en LM incompleto y un 9 por ciento (9 de 100) en el GC (p= 0,003). Al analizar la presencia de colelitiasis y nivel neurológico sobre y bajo T10 (24,1 y 25,5 por ciento respectivamente) tiempo de evolución de la LM, edad, obesidad y Diabetes mellitus, no se evidencia asociación significativa. Conclusiones: LM varones es factor de riesgo importante en el desarrollo de colelitiasis y debe ser considerada una complicación tardía en estos pacientes.

Complicaciones tardías en el lesionado medular / Late complications in the medullar wounded

Durante las últimas décadas, la sobrevida de los lesionados medulares ha registrado una marcada y continua prolongación. Debido a este hecho, el número de pacientes con lesión medular que llegan a edades avanzadas, ha presentado un importante incremento también. Sin embargo, el aumento de las expectativas de vida de estos pacientes ha traído consigo una mayor incidencia de complicaciones tardías, que progresivamente comienzan a adquirir mayor relevancia durante la evolución posterior a la injuria medular, dado que implican mayor discapacidad para el afectado. Los autores de este trabajo analizan las principales complicaciones tardías de los lesionados medulares, correspondientes a las que afectan a los sistemas nervioso, músculo-esquelético y gastrointestinal